Lagonda Rapiers

3 minute(s) of a 484 minute read

Hello Mike, thank you for your interest.I will have to check the new pistons when they arrive but I would think that they will be the same depending if they use the original spec or copy the sample pistonIf the original spec approx 10 : 1 if a copy of the sample 8.5 : !, There are no other changes planed. The tops of the original pistons had ceramic coating, I will probably ask for this to be done again.I had some material machined off the top of the original pistons when I de-tuned the engine some years ago. This is something I will have to check when they arrive.It is a much more pleasant car to drive on the roads since it was de-tuned. Instead of having to run it between 3,500 and 6,000 rpm it now pulls from about 1,750/2,000 rpm and seldom goes over 4,500/5,000 rpm.  Valve timing was 35/75 it is now 20/60. Lift at the cam is .310.  It like to run on 98/100 octane. It can use 95 but never 91 that is when I ran into trouble when all I could obtain in "out-back" New South Wales was 91 or worse. Some "Service Stations" had just the one pump and whatever came out of the hose was certainly not High-octane petrol. It was probably OK when I had about half a tank of 98/95 and was running on a mixture but after a couple of re-fills of junk-fuel XXXX, or as the French would say Merde!By comparison with the above details the original 1934 factory valve timing was:- The inlet valves opened at TDC and closed 52 degrees after BDC. The exhaust valves opened 55 degrees before BDC and closed 8 degrees after TDC. In 1934 the compression ratio was 7.5:1. At the time this would have been considered quite high.  Bj

1-24-2017

Hello Mike, thank you for your interest.I will have to check the new pistons when they arrive but I would think that they will be the same depending if they use the original spec or copy the sample pistonIf the original spec approx 10 : 1 if a copy of the sample 8.5 : !, There are no other changes planed. The tops of the original pistons had ceramic coating, I will probably ask for this to be done again.I had some material machined off the top of the original pistons when I de-tuned the engine some years ago. This is something I will have to check when they arrive.It is a much more pleasant car to drive on the roads since it was de-tuned. Instead of having to run it between 3,500 and 6,000 rpm it now pulls from about 1,750/2,000 rpm and seldom goes over 4,500/5,000 rpm.  Valve timing was 35/75 it is now 20/60. Lift at the cam is .310.  It like to run on 98/100 octane. It can use 95 but never 91 that is when I ran into trouble when all I could obtain in "out-back" New South Wales was 91 or worse. Some "Service Stations" had just the one pump and whatever came out of the hose was certainly not High-octane petrol. It was probably OK when I had about half a tank of 98/95 and was running on a mixture but after a couple of re-fills of junk-fuel XXXX, or as the French would say Merde!By comparison with the above details the original 1934 factory valve timing was:- The inlet valves opened at TDC and closed 52 degrees after BDC. The exhaust valves opened 55 degrees before BDC and closed 8 degrees after TDC. In 1934 the compression ratio was 7.5:1. At the time this would have been considered quite high.  Bj